Substrates that include one or more semiconductor materials are used to form a wide variety of semiconductor structures and devices including, for example, integrated circuit (IC) devices (for example, logic processors and memory devices), radiation-emitting devices (for example, light-emitting diodes (LEDs), resonant cavity light-emitting diodes (RCLEDs), vertical cavity surface emitting lasers (VCSELs)), radiation sensing devices (for example, optical sensors) and electronic devices utilized in power control systems. Such semiconductor devices are conventionally formed on and/or in a surface of a semiconductor substrate.
Historically, semiconductor substrates used in the semiconductor device manufacturing industry comprise thin discs or “wafers” of silicon material. Such wafers of silicon material are fabricated by first forming a large generally cylindrical silicon single crystal ingot and subsequently slicing the single crystal ingot perpendicularly to its longitudinal axis to form a plurality of silicon wafers. The wafers are then cut into dies by cutting “streets” in the wafers. Silicon wafers may have diameters as large as about thirty centimeters (30 cm) or more (about twelve inches (12 in) or more). Although silicon wafers generally have thicknesses of several hundred microns (for example, about 700 microns) or more, only a very thin layer (for example, less than about three hundred nanometers (300 nm)) of the semiconductor material on a major surface of the silicon wafer is actually used to form active devices on the silicon wafer.
A wide variety of engineered substrates are known in the art and may include semiconductor materials such as, for example, silicon (Si), germanium (Ge), silicon carbide (SiC), III-V type semiconductor materials, and II-VI type semiconductor materials. For example, an engineered substrate may include an epitaxial III-V type semiconductor material formed on a surface of a base substrate, such as aluminum oxide (Al2O3) (which may be referred to as “sapphire”).
Individual semiconductor structures (e.g., dies or wafers) may be relatively thin and difficult to handle with equipment for processing the semiconductor structures. Thus, so-called “carrier” dies or wafers may be attached to the actual semiconductor structures that include therein the active and passive components of operative semiconductor devices. The carrier dies or wafers do not typically include any active or passive components of a semiconductor device to be formed. Such carrier dies and wafers are referred to herein as “carrier substrates.” The carrier substrates increase the overall thickness of the semiconductor structures and facilitate handling of the semiconductor structures (by providing structural support to the relatively thinner semiconductor structures) by processing equipment used to process the active and/or passive components in the semiconductor structures attached thereto that will include the active and passive components of a semiconductor device to be fabricated thereon.
Laser lift-off methods may be used to separate portions of substrates in the fabrication of semiconductor structures. For example, an epitaxial layer may be grown on a first substrate, and individual chips may be formed in the epitaxial layer. A second substrate may be bonded to the epitaxial layer. A laser heats the first substrate and releases it from the epitaxial layer. The individual chips remain attached to the second substrate. Such methods are described in, for example, U.S. Pat. No. 7,754,511, issued Jul. 13, 2010, entitled “Laser Lift-Off Method,” and U.S. Patent Application Pub. No. 2011/0132549, published Jun. 9, 2011, entitled “Laser Lift Off Systems and Methods,” the entire disclosures of each of which are incorporated herein by this reference.